Refrigerating apparatus



Jan. 24, 1956 R. M. sMlTH 2732126 RFRIGRTING APPARATUS Filed Aug. 27, 195] 5 Sheeats-Shee'fI 1 W 20 IVENTOR Jan. 24, 1956 Filed Aug. 27 1951 R. M. SMITH REFRIGERATING APPARATUS 5 Sheets-Sheet 2 Jan. 24, 1956 R. M. sMlTH 2732126 REFRGERATING APPRATUS 5 Sheets-Sheet 3 Filed Aug. 27 1951 Jan. 24, 1956 Filed Aug. 27, 1951 R. M. sMn'H 2,732,l26 REFRIGERATING APPARATUS 5 Shee'S-Sheet 4 |45 B ZU w ZVJNVENTR. FIG. 8

Jan. 24, 1956 R. M. sMlTH 2,732,126

REFRIGERATING APPARATUS Filed Aug. 27, 1951 5 Sheets-Sheet 5 Flc. IO

7% mym.

United States Patent REFRIGERATING APPARATUS Rolf M. Smith, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application August 27, 1951, serial No. 243,799

7 claims. (ci. 230-145) This invention is related in a general way to refrigerating apparatus and more particularly to pumps and compressors.

It is an object of my invention to provide a compressor capable of Operating in all speed ranges, which is small, compact, and has high capacity and high volumetric efficiency.

It is another object of my invention to provide a rotary compressor of the type having a plurality of fixed pumping chambers with one or more simple mechanically controlled inlet port arrangements for each chamber which will close substantially when that chamber is filled to its maximum capacity on the suction stroke.

It is another object of my invention to provide a rotary compressor of the type having a plurality of fixed pumping chambers with one or more simple mechanically controlled inlet port arrangements for each chamber in which the impeller completes the covering o'f the inlet ports substantially when that chamber is filled to its maximum capacity on the sucton stroke and continues the coveringruntil the completion of the compression stroke.

It is another object of my invention to provide a rotary compressor of the type having a plurality of fixed pumping chambers with one or more simple mechanically controlled inlet port arrangements for each chamber which have free inlet fiow, and which take full advantage of the inertia of the gas as long as the inertia is effective and then is sharply cut off.

To attain these objects, I have provided a compressor divided into two fixed pumping chambers byv a pair of diametrically opposite sealing vanes which provide a continuous seal between the cylinder wall and the eccentrically operated impeller at two points 180 apart. The compressor is provided with conventional outlet ports, but a simple, novel, highly eflicient inlet port is provided in the one or both plane walls of each pumping chamber directly adjacent the vane. These ports are arranged so that they will be covered between about 210 and 270 in advance of the completion of the compression stroke.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a sectional view through one form of refrigerator compressor taken substantially along the line 1-1 of Fig. 3;

Fig. 2 is a sectional view taken substantially along the line 2 2 of Fig. 3;

Fig. 3 is a sectional view taken substantially along the line 3-3 of Fig. 1;

Fig. 4 is a fragmentary view of sectional view taken substantially along the line 4 4 of Fig. 3;

Fig. 5 is a view partly diagrammatic showing the 1oca-,

tion of the impeller relative to theupper inlet port at the initial opening of the port during the suct'ion stroke;

Fig. 6 is a similar view showing the first position in which the upper port is completely uncovered;

Fig. 7 is a view similar to Figs. 5 and 6 showing the last position of the impeller in which the upper port is completely uncovered;

Fig. 8 is a view similar to Figs. 5 to 7 showing the first position in which the upper port is completely covered to begin the compression of the gas;

Fig. 9 is a diagrammatic view illustrating the location and the shape of the inlet and outlet ports; and

Fig. 10 is a fragmentary sectional view of a modified form of the invention having dual inlet ports.

Referring now to the drawings and more particularly to Fig. l, there is shown a sealed casing 20 provided with an inlet fitting 22 and an outlet 24. To the inlet fitting 22 is connected a suction line valve 26 having a valve stem 23 which may be turned by a key to close the valve so as to seal the inlet 22 of the compressor. The compressor is provided with an eccentric shaft 30 which may be driven by an electric motor or other suitable driving means, not shown. Within the sealed casing 20, the compressor is provided with a bearing support 32 provided with a bearing bushing for supporting the main bearing 34 of the eccentric shaft 30. This main bearing support 32 forms a part of the sealed casing 20. I't contains a snction cavity 36 which extends in a path of 360 surrounding the shaft 30. This cavity 36 is closed by an end plate 40. The cavity 36 is connected by a passage 42 through the inlet 22 with the interior of the suction line valve 26.

The shoulder at the right end of the bearing portion 34 is provided with a seal ring 44 which is sealed to the shaft 30 by a suitable gasket. This seal ring 44 revolves With the shaft 30. Contacting the seal ring 44 is a second seal ring 46 held in engagement with the seal ring 44 by the large coil spring 48. The seal ring 46 has connected to it one end of the metal bellows 50, the other end of which is connected to a fiange member 52 which is clainped into sealing relationship to the plate 40 by the clamping ring 54. This seals the seal ring 46 to the main bearing support 32 and prevents its rotation.

Fixed 'to the bearing support 32 is the cylinder 56. This cylinder 56 is provided with two vane slots 58 and 60 containing the vanes 62 and 64. These vanes 62 and 64 are normally held in engagement with the impeller 66 by coil springs such as the coil Springs 68.

The impeller 66 is mounted upon an eccentric portion 70 of the shaft 30. Upon the left side of the cylinder 56, there is provided a valve plate 72 containing two diametrically opposite discharge valves 74 which connect directly with the discharge grooves 76 formed in the cylinder 56 directly on the compression side of the vanes 62 and 64. The discharge valves 74 discharge directly into the interior of the sealed casing 20 so that the compressed gas may flow directly through the outlet 24. Any lubricant in the compressed gas can collect in the bottom of the sealed casing 20.

The valve plate 72 is provided with a bearing bushing for supporting the bearing portion 78 of the shaft 30. At the left side of the bearing portion 78, there is provided an eccentric portion 80 which serves as the impeller of an oil or lubricant pump. Cooperating with this eccentric portion S0 is a slidable vane 82 held in engagement With the eccentric portion 80 by the compression spring 84 which is held in place by a small plate S6. The lubricant 88, such as mineral oil, is provided in the bottom of the casing 20.

A tube extends beneath the level of the lubricant 88 and connects with a passage 92 which extends to the inlet side of the chamber within which operates the eccentric 80. Upon the opposite side of the vane 82, there is a passage 94 (see Fig. 1) extending toran annular groove 96 in the bearing portion 78. This annular groove 96 feeds lubricant to a central lubricant passage 98 extending through the shaft and provided with branch passages 121 and 123 for feeding lubricant to the bearing portions 70 and 34. The seal rings 44 and 46 are provided with lubricant which escapes from the end of the bearing portion 34. A -pressure relief valve assembly 125 connects to the cavity within which the shaft seal 46, 48 and 50 is located so as to limit the lubricant pressure which may be applied to the seal.

At the opposite end of the shaft 30, there are provided the thrust plates 12"/ and 129. Between the surfaces of these thrust plates 127 and 129, there is provided a thrust member 131 which is flanked by bearing rings 133 on either side which are supported by the adjacent surfaces of the thrust plates 127 and 129. The counterbalancing disk 135 is fastened on to the end of the shaft 30 by the screw 137. This screw also holds the hub of the counterbalancing disk 135 tightly in engagement with the thrust member 131 which is thereby tightly held against the bearing portion 139 supported by the thrust plate 127. The thrust bearing rings 133 are supplied with lubricant through the branch passage 141 extended at a 45 angle from the central passage 98 to thc adjacent side of the thrust member 131. Through this system, lubricant is force fed to all the major wearing surfaces of the compressor. The vanes receive lubricant by the lubricant which naturally leaks into the compression Chamber.

The compression Chamber, of course, is formed between the impeller 66 and the cylinder 56. The vanes 62 and 64 divide the space between the impeller 66 and the cylinder 56 into two entirely separate pumping chambers 143 and 145. The pumping Chamber 145 is provided with a discharge passage 76 while the pumping Chamber 143 is provided with the discharge passage '77. The impeller as viewed in Figs. 5 to 8 inclusive is revolved in a counterclockwise direction. The discharge passages '76 and 77 are located directly in advance of their respective vanes 62 and 64.

The use of two vanes instead of a single vane makes possible an increase in capacity of the compressor as much as without increasing the size of the Compressor. This results from the fact that when two vanes are used, one of the compression spaces is discharged every 270 while in a single vane compressor, there is a discharge from the compression space every 360.

The inlet ports cannot be placed in the peripheral wall of the cylinder without employing a check valve as can be done in a single vane compressor. To attain the maximum output from a two-vane compressor, it is necessary that there be free inlet flow into the compression space through the inlet port, and the inlet port must be rapidly and sharply closed at the proper time. This requires an inlet port arrangement which allows free flow of gas from the annular space 36 into each of the compression spaces during the suction stroke. This free flow makes it possible to make full use of the inertia of the gas flowing into the compression Chamber so as to obtain the maximum capacity and efiiciency.

Figures 5 to 9 show one particular shape of inlet ports and one particular location of such ports. This example is based upon a rotary compressor having an inner diameter of approximately 3% inches (3.2473), an impeller diameter of 2.8373 inches, and an eccentricity of .205 inch. The inlet ports 221 and 223 are located so that they will be closed about 245 in advance of the completion of the compression stroke. The ports are shaped and located as follows: A Circle having a radius of .205 inch, which is the designed eccentricity, is laid out. On this Circle, there is located a point 245 in advance of the vane which determines the location of the completion of the compression stroke. From this point, there is inscribed an arc having a radius equal to the radius of the impeller 66, namely, 1.418 inches approximately.

The inner edge of the port is not particularly Critical and may be formed as desired to make a port of adequate cross sectional area. In the present example, the inner edge of each inlet port is made by inscribing an arc from the center of the axis of the drive shaft 30. The length of this arc is slightly less than the radius of the impeller minus the eccentricity. This edge substantially coincides with the path of the edge of the impeller 66. The exact value chosen is the radius of 1.187 inches. The inlet ports extend in the clockwise direction substantially until they meet the edge of the adjacent vane such as the vanes 62 and 64. The inlet ports extend in the opposite direction substantially to the meeting point of the two arcs.

With the inlet ports so laid out, the upper inlet port 221 will begin to open after the suction stroke procceds about as shown in Figure 5. The inlet port 221 will be fully open after the impeller 66 has been moved through about l67 in the suction stroke as shown in Figure 6. The impeller 66 will begin to close the suction port 221 after it has been revolved through about 250. The inlet port 221 will be completely closed when the impeller 66 has revolved about 295 after the beginning of the suction stroke or about 245 in advance of the completion of the compression stroke. This will 'insure eificient operation of the compressor when the suction gas is at a medium densty. To obtain maximum etficiency when a lighter gas is used, the point on the .205 inch circle should be more than 245 in advance of the completion of the compression stroke with a limit of about 270. For a more dense suction gas, the point on the .205 inch Circle should be less than 245 in advance of the completion of the compression stroke with a limit of about 210. The extreme limits of this inlet closing point on the .205 inch Circle should be between about 270 and 2-10 in advance of the completion of the compression stroke.

By the use of an inlet port arrangement in which the impeller is used to cover and uncover the inlet ports at the proper time, there are provided mechanically opened and closed inlets without the use of any additional working parts. Reliability of the compressor is thereby increased, and by reason of the large area possible and the quick opening and closing, a maximum amount of suction gas can be drawn into the compression space. This assures high capacity and high volumetric efiiciency.

In Fig. 10, there is shown the mid-portion of a compressor in which the parts not shown are similar to those in Figs. 1 to 9. This compressor includes a sealed casing 320. The compressor is provided With an eccentric shaft 330 which may be driven by an electric motor or other suitable driving means, not shown. Within the sealed casing 320, the compressor is provided with a bearing support 332 provided with a bearing bushing for supporting the main bearing 334 of the eccentric shaft 330. The main bearing 334 is made longer than the main bearing 34 to increase its carrying capacity. The bearing support 332 contains a suction cavity 336 extending in a path of 360 surrounding the shaft 330. This cavity 336 is connected with the suction line in a manner shown in Fig. 1.

Fixed to the bearing support 332 is the cylinder 356. This cylinder 356 is provided with vanes and vane slots, not shown, which are similar to those shown in Figs. 1 to 9. The impeller 366 is mounted upon an eccentric portion 370 of the shaft 330. To increase the capacity of the compressor, the cylinder 356, the impeller 366, and the eccentric portion 370 are made substantially twice as long in the axial direction as the corresponding parts in Figs. 1 to 9. However, although not necessary, I have retained the same diameter and eccentricity of the eccentric portion 370 as well as the same diameter of the impeller 366 and the cylinder 356.

Upon the left side of the cylinder 356, there is proi vided a valve plate 372 containing two diametrically opposite discharge valves, not shown, which are similar to lthe discharge valve 74 in Figs. 1 to 9 which connect directly with discharge grooves similar to the grooves 76. The valve plate 372 is provided with bearing bushing for supportinlg the bearing portion 378 of the shaft 330.

At the left side of the bearing portion 378, there is provided an eccentric portion 380 which serves as the impeller of the oil or lubricant pump which delivers lubricant through passages in the shaft 330 to the various bearings in the same manner as shown in Figs. 1 to 9. Cooperating with this eccentn'c portion 380 is a slidable -vane 382 held in engagement with the eccentric portion 380 by the compression spring 384 held in place by a small plate 386. The lubricant 388, such as mineral oil, is provided in the bottom of the sealed casing 320.

In the valve plate 372, there is provided opposite the inlet port 421, a second inlet port 422 connected by the passage 424 in the valve plate 372 and the passage 426 in the cylinder 356 with the cavity 336. Upon the diametrically opposite side of the cylinder 356, there are provided the inlet ports 423 and 425. The inlet port 425 is connected by the passage 427 in the discharge plate 372 and the passage 429 in the cylinder 356 with the cavity 336. The ports 421, 422, 423, and 425 are similar to the ports 221 and 223 and are located with respect to the vanes in a similar manner as described in connection with Figs. 1 to 9.

This arrangement makes possible the drawing in of the suction 'gas from both sides of the compression space, thereby insuring substantially the same efliciency from the cylinder 356 which is nearly twice as long in the axial direction as can be obtained with the cylinder 56. The passages 424 and 427 are closed by a plate 429 sealed by a suitable gasket 430. Thus, in this Fig. 10, I have shown how my invention can be applied to a compressor which is much longer in the axial direction than the one shown in Figs. 1 to 9. L

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. A rotary compressor including an impeller casing provided with spaced parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation with the spaced walls of the casing, a plurality of spaced sealing means extending between a plurality of spaced points on the casing and on the impeller to divide the space between the impeller and the casing into a plurality of pumping chambers, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the round wall surface of the casing, a separate inlet port for each pumping chamber in the plane wall surface adjacent one side of each sealing means located so as to be covered and uncovered by the impeller during each revolution, the radially outer edge of each of said inlet ports substantially coinciding with the adjacent peripheral portion of the impeller when the impeller is about of a revolution in advance of the completion of the compression stroke, and outlet means for each of said pumping chambers.

2. A rotary compressor including an impeller casing provided with spaced parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation with the spaced walls of the casing, a plurality of spaced sealing means extending between a plurality of spaced points on the casing and on the impeller to divide the space between the impeller and the casing into a plurality of pumping chambers, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the.

round wall surface of the casing, a separate inlet port for each pumping chamber in the plane wall surface adjacent one side of each sealing means located so as to be covered and uncovered by the impeller during each revolution, the radially outer edge of each of said inlet ports substantially coinciding with the adjacent peripheral portion of the impeller when the impeller is about 245 in advance of the completion of the compression stroke, and outlet means for each of said pumping chambers.

3. A rotary compressor including an impeller casing provided with spaced parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation with the spaced walls of the casing, a plurality of -spaced sealing means extending between a plurality of spaced points on the casing and on the impeller to divide the space between the impeller and the casing into a plurality of pumping chambers, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the round wall surface of the casing, a separate inlet port for each pumping chamber in the plane wall surface adjacent one side of each sealing means located so as to be covered and uncovered by the impeller during each revolution, the radially outer edge of each of said inlet ports substantially coinciding with the adjacent peripheral portion of the impeller when the impeller is between 210 and 270 in advance of the completion of the compression stroke, and outlet means for each of said pumping chambers.

4. A rotary compressor including an impeller casing provided with parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation with the spaced walls of the casing, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the round wall surface of the casing, two spaced sealing means extending between two diametrically opposite points on the casing and the impeller to divide the space between the impeller and the casing into two equal pumping chambers, a separate inlet port in the plane wall surface adjacent one side of each sealing means located so as to be covered and uncovered by the impeller during each revolution, the radially outer edge of each of said inlet ports coinciding with the adjacent peripheral edge of the impeller when the impeller is about 65 in advance of the sealing means, and outlet means for each of said pumping chambers.

5. A rotary compressor including an irnpeller casing provided with parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation with the spaced walls of the casing, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the round wall surface of the casing, two spaced sealing means extending between two diametrically opposite points on the casing and the impeller to divide the space between the impeller and the casing into two equal pumping chambers, and separate inlet ports in the opposite plane wall surfaces adjacent one side of each sealing means located so as to be covered and uncovered by the impeller during each revolution, the radially outer edge of each of said inlet ports coinciding with the adjacent peripheral edge of the impeller when the impeller is about 65 in advance of the sealing means, and outlet means for each of said pumping chambers.

6. A rotary compressor including an impeller casing provided with spaced parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in s'ealing relation with the spaced walls of the casing, a plurality of spaced sealing means extending between a plurality of spaced points on the casing and on the impeller to divide the space between the impeller and the casing into a plurality of pumping chambers, means for moving the peripheral surface of the impeller progressively into sealing relation with successive portions of the round Wall surface of the casing, a separate inlet port for each pumping Chamber in the plane wall surface adjacent one side of each sealing means, the radially outer edge of each of said inlet ports extending upon` a radius substantially equal to the radius of the impeller struck substantially from a point on the path of movement of the axis of the impeller located on the opposite side of the extended center line of the adjacent sealing means, and outlet means for each of said pumping chambers.

7. A rotary compressor including an impeller casing provided With spaced parallel plane wall surfaces and a round wall surface extending between the plane wall surfaces, an impeller within the casing having surfaces in sealing relation With the spaced walls of the casing, a plurality of spaced sealing means extending between a plurality of spaced points on the casing and on the impeller to divide the space between the impeller and the casing into a plurality of pumping chambers, means for moving the peripheral surface of the impeller' progressively into sealing relation with successive portions of the round wall surface of the casing, a separate inlet port for each pumping Chamber in the plane wall surface adjacent one side of each sealing means, the radially outer edge of each of said inlet ports extending upon a radius substantially equal to the radius of the impeller struck substantially from a point on the path of movement of the axis of the impeller located on the opposite side of the extended center line of the adjacent sealing means, the radially inner edge of each of said ports extending upon a radius substantially equal to the difference between the radius of the impeller and the eccentricity of the impeller relative to the axis of the pumping Chamber struck substantially from the axis of the pumping Chamber, and outlet means for each of said pumping chambers.

References Cited in the file of this patent UNITED STATES PATENTS 45,596 Foster Dec. 27, 1864 918,906 Poppenhusen et al. Apr. 20, 1909 1,158,467 Evans Nov. 2, 1915 1,459,637 Poyet June 19, 1923 [929,997 Wilson Oct. 10, 1933 1,996.620 Ketterer Apr. 2, 1935 2,155,756 Firestone et al Apr. 25, 1939 2,212,717 Penn Aug. 27, 1940 2,4-20,442 Rataiczak May 13, 1947 2,476,383 Porteous July 19, 1949 FOREIGN PATENTS 560,068 Germany Sept. 28, 1932 

